Field of the Invention
Embodiments of the present invention relate generally to three-dimensional printing and, more specifically, to techniques for approximating three-dimensional curves using foldable beams.
Description of the Related Art
A typical three-dimensional (3D) printer generates a 3D solid object based on a 3D printable digital model, such as a 3D mesh of triangles. In operation, the 3D printer creates the 3D object from bottom to top. For instance, if the 3D model were to represent a candy cane, then the 3D printer would print successive layers of material beginning with a layer corresponding to the bottom of the stem and ending with a layer corresponding to the top of the hook. To prevent un-supported layers (such as the hook of a candy-cane) from collapsing and/or drooping onto previously printed layers or the ground during the printing process, 3D printers typically enhance the 3D model around the un-supported layers with “support structures.”
In general, support structures are designed to ensure the integrity of the material that forms the 3D object throughout the 3D printing process. In that vein, 3D printers oftentimes generate support structures in a different type of material than the material used to generate the geometries associated with the actual 3D object being printed. After the 3D printer generates the 3D object, a designer usually performs post-processing operations to remove the now-extraneous support structures and reveal the desired 3D object. For instance, the designer may break off or dissolve the support material.
One drawback to removing the support materials after printing a 3D object is that the associated post-processing techniques can cause perceivable defects in the 3D object. For example, if the support material is broken off, then rough edges may be apparent in the 3D object. And, if the support material is dissolved, then the color and/or texture of the 3D object may be uneven. Consequently, some designers modify the 3D model to reduce the amount of support material required during 3D printing.
In general, the amount and structure of the support material correlates to the number and significance of overhangs specified by the 3D model. Most 3D printers can print 3D objects with some amount of overhang without having to include support material. More specifically, each such 3D printer is associated with an overhang angle threshold, also known as the maximum draft angle. The overhang angle threshold is the maximum angle of a local surface patch relative to the horizontal print bed that the 3D printer is configured to print without adding support material to ensure the integrity of the 3D object during printing.
In one approach for reducing the amount of support required during 3D printing, the designer identifies which of the angles included in the 3D model exceed the overhang angle threshold. The designer then modifies the 3D model to reduce the magnitude of one or more of the identified overhang angles. The designer repeats this process until satisfied with the appearance of the 3D model. While this incremental adjustment process may yield acceptable results for simple 3D objects, adjusting complex 3D objects to reduce overhang angles without unacceptably distorting the desired shapes of the 3D objects can be tedious and quite time consuming. Further, even with a deliberate, careful approach to reducing the identified overhang angles, the remaining amount of support material and/or the modifications to the 3D objects are oftentimes still unacceptable from a design perspective.
As the foregoing illustrates, what is needed in the art are more effective techniques for reducing support materials generated during 3D printing.